The present invention relates a novel approach to shielding undesirable background electromagnetic radiation from radiation detectors operating in the infrared (IR) region of the energy spectrum. These IR radiation detectors and the background shields, called cold shields, operate at reduced temperatures so that the cold shield not only prevents warm background radiation from arriving at the radiation detector but itself does not emit radiation in the band seen by the radiation detector either. The novel approach departs from the common techniques used in the design of these cold shields without limiting detector performance.